The Wolfsburg midfielder says that he remains mystified as to why he was frozen out by the Portuguese manager at Stamford Bridge before being sold in January 2014
The Belgium international was considered one of the most exciting young talents in Europe when he joined the Blues from Genk in January 2012 for a fee of €8 million (£5.9m).
However, after being loaned back to Genk for the remainder of the season, De Bruyne was then allowed to spend the following campaign at Werder Bremen.
The versatile midfielder returned to Stamford Bridge in the summer of 2013, hoping to establish himself as a first-team regular under new boss Mourinho, but he featured just three times in the Premier League before being sold to Wolfsburg in January 2014 for €18m (£13.2m).
The 23-year-old has since flourished at the Volkswagen Arena, admitting that he is glad to be away from both Chelsea and Mourinho.
"I feel at home at Wolfsburg and, in this moment, I'm even willing to sign a new contract," De Bruyne told Sport Bild.
"It's a club on a rapid rise, also from an economic point of view - not yet like Bayern Munich, obviously, but the club is growing.
"The choice to join Chelsea was not the best. Being at Chelsea is like being in a different world.
"Mourinho didn't explain to me why I was not playing. Maybe things would have been different if Chelsea had paid €45m for me, rather than €8m. A higher transfer fee maybe would have afforded me greater consideration."
De Bruyne, who played a key role in Wolfsburg's rout of Bayern Munich earlier in February, has racked up eight goals and 12 assists in 22 Bundesliga appearances so far this season.